Screening device



1964 R. G. McKE SCREENING DEVICE Filed March 26, 1962 United States Patent 3,151,781 SCREENING DEVICE Robert G. McKee, Chicago, 111., assignor to Gerald G. Kraft, Chicago, Ill. Filed Mar. 26, 1962, Ser. No. 182,548 4 Claims. (Cl. 222-189) This invention relates to a lump filtering device, and more specifically, to a device particularly adapted to prevent the clogging of dispensers for granular materials and other finely-divided materials.

A principal object of the present invention is to provide an anti-clogging filter for use in the dispensing of salt, sugar and other finely-divided materials which, under certain conditions, agglomerate and form large lumps tending to clog the discharge opening of a dispenser. A specific object is to provide a filter for granular material dispensing devices which is capable of selectively restraining larger particles or lumps without becoming clogged itself. Another object is to provide a lump filtering device of simple and inexpensive construction which may be readily inserted into a dispensing container for the dispensing of salt, sugar or other hygroscopic materials. Another object is to provide a highly effective lump filtering device which may be readily washed or otherwise cleaned because of its exposed surfaces.

Other objects will appear from the specification and drawings in which:

FIGURE 1 is a perspective View of a dispenser equipped with a lump filtering device embodying the present invention;

FIGURE 2 is a plan view of the lump filter;

FIGURE 3 is an elevational view of the lump filter showing the separators when viewed from their ends;

FIGURE 4 is an elevational view similar to FIGURE 3 but showing the separators when viewed from the side;

FIGURE 5 is an enlarged broken perspective view illustrating operation of the filtering device;

FIGURE 6 is another enlarged broken perspective view illustrating the operation of the lump filtering device.

In the structure illustrated in the drawings, the numeral 10 generally designates a dispensing container of the type commonly used in restaurants and other commercial establishments for dispensing sugar. The container is provided with a body 11, normally formed from a transparent material such as clear glass, and a cap 12 threaded upon the open end of the body. The cap is domed and is provided with a discharge opening 13 adapted to be closed by a hinged cover 14 when the container is placed in upright position. When the container is tipped forwardly, closure 14 drops open and the contents of the container flow in a stream 15 through the discharge opening 13. Since such a container is entirely conventional and is well known in the art, further description of its structure and operation is believed unnecessary for the purpose of disclosing the environment for the lump filter of the present invention.

The lump filtering device is designated generally by the numeral 16 and consists essentially of a fiat aperture plate 17 provided along one side thereof with a plurality of notched strips 18. Preferably, the strips and plate are integrally formed although, if desired, the strips may be formed separately and then cemented or otherwise rigidly secured to the plate.

As shown most clearly in FIGURE 2, the plate is provided with a plurality of circular openings 19 extending therethrough, the openings being arranged in parallel rows and each being of smaller diameter than discharge opening 13. The elongated notched strips are disposed in spaced parallel relation and extend between the parallel Patented Oct. 6, 1964 rows of openings 19. Thus, except for the terminal rows of openings, each row is bordered on opposite sides by a pair of the notched strips 18, such strips in elfect defining channels with the openings 19 being disposed in the bottom walls of those channels.

The notches 20 of each of the strips are spaced apart along the free longitudinal edge thereof and define therebetween a plurality of spacer elements 21. In the illustration given, it will be noted that the spacer elements are generally rectangular in shape and that the notches are also rectangular in shape. While spacer elements and notches or other shapes may be provided, the width and depth of the notches must not exceed the diameter of the openings and preferably should be less than such diameter.

The lump filtering device is adapted to be disposed within a dispensing container, such as container 10, with the flat side thereof adjacent to but spaced slightly from the end wall of the container having the discharge opening. The spacer elements of the filter thus project into the interior of the containers body portion. The filter extends over an area at least as large as the internal cross sectional area of the container; in the illustration given, the diameter of the plate 17 is approximately the same as the external diameter of the container body adjacent the open end thereof and the edge portion of the plate is clamped against the open end of the container body by the threaded cap 12.

As the container is tipped to dispense granular material through the discharge opening thereof, large lumps and particles within the container migrate towards the filter where they engage the ends of spacer elements 21. FIGURES 5 and 6 illustrate such lumps 22 restrained by the plurality of spacer elements. Since the free ends of the spacer elements are disposed a substantial distance from openings 19, the large lumps are prevented from reaching and clogging such openings. At the same time, smaller grains or granules may readily pass beneath the restrained lumps and through the notches 20 into the channels defined by the parallel strips 18. The notches therefore serve as feed passages or ports for the parallel channels which in turn direct the finely-divided material into openings 19.

From the foregoing, it is believed apparent that the filter 16 is eifective in preventing large lumps of agglomerated granular material from reaching and clogging the discharge opening 13 of the container. The multiplicity of spacer elements which project into the interior of the container are effective in holding back large lumps and particles without at the same time restraining the flow of smaller-sized particles through the openings 19 in the plate.

The filter is preferably formed from a relatively nonhygroscopic plastic material especially where the filter is to be used in conjunction with the dispensing of salt, sugar or other granulated materials which might tend to cling to moisture-retaining surfaces. Polystyrene and polypropylene have been found efiective, although any other suitable plastic material may be used.

While the lump filter has been shown and described in combination with a cylindrical container for dispensing sugar, it is to be understood that the filter may be used industrially with containers of a wide variety of shapes for the dispensing or screening of any suitable finelydivided materials such as sand, gravel, chemicals, etc.

An embodiment of the present invention has been disclosed in considerable detail for purposes of illustration but it is to be understood by those skilled in the art that many of these details may be varied without departing from the spirit and scope of the invention.

I claim:

1. A screening device comprising a horizontal plate having rows of openings extending therethrough, said plate being provided with a plurality of rigid horizontally-elongated spacer elements arranged in series between said rows of openings and also projecting in a direction normal to the plane of said plate, the elements of each of said series being spaced apart to define feed passages for the flow of granular material into and through said openings and being provided with longitudinally-spaced transverse notches permitting the fiow of relatively small particles therethrough and through said openings while large lumps of material are restrained by said elements.

2. A lump screening device comprising a plate having rows of openings extending therethrough, a plurality of notched strips extending along one side of said plate between said rows, the notches of each of said strips extending transversely to provide a plurality of integral spacer elements extending normal to the plane of said plate, said notches permitting the flow of small particles of material between said spacer elements and through said openings while larger lumps of material are restrained by said elements.

3. The structure of claim 2 in which said notches extend from one longitudinal edge of each strip to a longitudinal mid line of said strip, the portion of each strip between said notches and said plate being imperforate for guiding the flow of granular material to said openings.

4. A lump screening device for dispensers of granulated materials comprising a plate adapted to be mounted within a dispensing container adjacent the discharge opening thereof, said plate having a plurality of openings therein, and a plurality of rigid spacer elements between said openings and extending normal to the plane of said plate into the interior of said dispenser, each spacer element being spaced apart from immediately adjacent spacer elements a distance no greater than the diameter of said openings in said plate and being provided with a plurality of longitudinally-extending transverse notches permitting the flow of small particles therethrough and through said openings while large lumps of material are restrained by said elements.

References Cited in the file of this patent UNITED STATES PATENTS 1,065,929 El ,July 1, 1913 1,449,553 Schlunke Mar. 27, 1923 1,731,115 Taylor Oct. 8, 1929 1,972,901 Peters Sept. 11, 193.4 3,031,107 Lucoco Apr. 24,1962

FOREIGN PATENTS 170,529 Switzerland Sept. -17, 1934 1,006,727 France Jan. 30, 19,52

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,151,781 October 6, 1964 Robert G. McKee It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the grant, lines 1 and 2, for "Robert G. McKee, of

Chicago, Illinois, assignor to Gerald G. Kraft, of Chicago, Illinois," read Robert G. McKee, of Chicago, Illinois, assignor of onehalf to Gerald G. Kraft, of Chicago, Illinois, line 11, for "Gerald G. Kraft, his heirs" read Robert G. McKee and Gerald G. Kraft, their heirs in the heading to the printed specification, lines 3 and 4, for "Robert G. McKee, Chicago, Ill. assignor to Gerald G. Kraft, Chicago, 111." read Robert G. McKee, Chicago, Ill. assignor of one-half to Gerald G. Kraft, Chicago, Ill.

Signed and sealed this 13th day of April 1965.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

1. A SCREENING DEVICE COMPRISING A HORIZONTAL PLATE HAVING ROWS OF OPENINGS EXTENDING THERETHROUGH, SAID PLATE BEING PROVIDED WITH A PLURALITY OF RIGID HORIZONTALLY-ELONGATED SPACER ELEMENTS ARRANGED IN SERIES BETWEEN SAID ROWS OF OPENINGS AND ALSO PROJECTING IN A DIRECTION NORMAL TO THE PLANE OF SAID PLATE, THE ELEMENTS OF EACH OF SAID SERIES BEING SPACED APART TO DEFINE FEED PASSAGES FOR THE FLOW OF GRANULAR MATERIAL INTO AND THROUGH SAID OPENINGS AND BEING PROVIDED WITH LONGITUDINALLY-SPACED TRANSVERSE NOTCHES PERMITTING THE FLOW OF RELATIVELY SMALL PARTICLES THERETHROUGH AND THROUGH SAID OPENINGS WHILE LARGE LUMPS OF MATERIAL ARE RESTRAINED BY SAID ELEMENTS. 